The worldwide percentage of new cars equipped with CD players peaked at 89% in 2008. But the ratio has slipped to 75% this year and is likely to sag to 35% by 2019, according to IHS Automotive.

A few car models—notably the Chevrolet Sonic and Spark small sedans—have eliminated a CD player entirely. Those vehicles simply provide plugs for such portable music sources as iPods or smartphones.

CD player installations peaked in 2008.

Consumer demand for in-car CD players is likely to fade as sales of CDs continue to shrink, says Mark Boyadjis, who heads infotainment market research for IHS.

The installation rate for CD players in new cars sold in the U.S. rose to 94% in 2005, according to Boyadjis. But he forecasts the only about 28% of new vehicles will offer and optic drive by 2019.

Still, the demise of the CD player will be gradual, Boyadjis says. One reason: Most current in-car audio systems are built to easily include or omit an optic disc drive, and redesigning them to eliminate that choice is a costly endeavor. On the other hand, carmakers figure that eliminating the CD player mechanism could contribute to better fuel economy by trimming about five pounds from a vehicle’s curb weight.

Analysts agree that optic drives are bound to disappear entirely at some point—just as the cassette tape player did in the American market when Lexus dropped the option three years ago. But even today’s trend of tapping portable music players for tunes may be short-lived as consumers switch to the next big thing: streaming music into their vehicles directly from the Internet.